DESCRIPTION (provided by investigator): Thirty-three million people worldwide are estimated to be living with HIV, half of which are women. Significant attention is being given to researching the effectiveness of antiretroviral therapy (ART) and its overall impact on lifetime survival. Improving the health of persons living with HIV, however, must also include securing the reproductive and sexual health needs of these individuals. As access to ART expands and the population of HIV-positives experiencing long-term survival multiplies, we are likely to see a growing class of persons who are aware of their serostatus and who want to live their lives as normally as possible, which may include having children. Increased fecundity and fertility have been documented in HIV-positive women after initiation of ART, but there remains little evidence or knowledge of whether or not these pregnancies are intended and how the reproductive decision making process is being managed in the treatment era. An inadequate understanding of how women are making reproductive decisions limits the ability of providers to deliver either the reproductive health care or ART care most appropriate to their patients'needs. The overall objective of this study is to further our understanding of fertility desires, reproductive decision making processes and reproductive health outcomes in HIV-positive women on ART. SPECIFIC AIMS: (1) to characterize reproductive decision-making processes in a clinical cohort of non- pregnant, HIV-positive women with access to antiretroviral therapy in South Africa;(2) to compare incidence rates of pregnancy between women on ART regimens that use the drug efavirenz versus nevirapine as a non- nucleoside reverse transcriptase inhibitor (NNRTI). METHODS: By aim: (1) We will conduct a prospective clinical cohort study of 800 HIV-positive, non-pregnant women who are currently receiving ART in South Africa. In-depth, structured surveys will be given to the women at baseline regarding their reproductive history, relationship status and intentions to become pregnant in the future. Pregnancy status and therapy regimens will be collected monthly over one year of follow-up during routine clinic visits. A decision analysis approach will be used to determine the clinical, behavioral and environmental factors that best predict pregnancy in HIV-positive women. The predictive accuracy of these findings will be compared to the sensitivity of simply asking about fertility intentions. (2) Pregnancy and ART data will be collected monthly over one year to compare differences in pregnancy incidence rates between efavirenz and nevirapine treatment groups. Cox proportional hazards models will compare pregnancy risk between the two treatment groups, controlling for time-varying CD4 count and contraceptive use. Early pregnancy loss will be reported as a secondary outcome of interest. PUBLIC HEALTH RELEVANCE: Drug treatment for HIV-positive individuals is expanding worldwide and is allowing for longer survival as well as increased fertility for women on treatment. There is currently little knowledge about the intentions of HIV positive women, nor how to manage reproductive decision making in this new era of treatment. The overall objective of this study is to further our understanding of fertility desires, reproductive decision making processes and reproductive health outcomes in HIV-positive women on treatment.